Diaphragm-horn



H. S. A. RYDBERG. DIAPHRAGM HORN.

APPLICATION FILED APR. 15. 1919.

Patented Apr. 13, 1920.

- ornron HEDGE SVEN ALBERT RYDBERG, OF MABMO, SWEDEN.

DIAPHRAGM-HORN.

To all whom it may concern:

Be it known that I, Hnnen SVEN ALBERT RYDBERG, a citizen of Sweden, residing at Malmo, county of Malmohus, Sweden, have invented certain new and useful Improvements in Diaphragm-Horns, of which the following is a specification.

The invention relates to an improvement in diaphragm horns operated by a gaseous or fluid medium that is pressed between a membrane and an edge resting against said membrane in such a way that the membrane, the actuating medium and the medium surrounding the siren are put into vibration. In such horns it is known to introduce the pressure medium through a pipe arranged centrally in relation to the membrane, this pipe being placed perpendicularly to the membrane, 11. e. in such a way that it is parallel with the longitudinal direction of the apparatus, and hereby the advantage is obtained that the pressure medium is inclosed within the smaller interior part and is brought to act upon the most flexible part of the membrane, i. e. at its center, but the disadvantage remains that the membrane must be made unnecessarily large in order to make it possible to utilize the sound waves in the desired direction, '5. e. in a sound funnel surrounding the pressure pipe, as this interior pipe takes up just the space. that should be totally free for obtaining the highest possible efliciency. This compulsory enlargement of the membrane beyond what is necessary for its satisfactory function causes all other dimensions to be extensively enlarged, whereby the apparatus turns out disproportionally large. These inconveniences are remedied by the present invention by means of which the apparatus as a whole also will be much simplified.

A characteristic feature of the invention is that the edge resting against the membrane consists of the end of the admission pipe for the driving medium and that this pipe is connected with an inlet port in the wall of the chamber that forms the outlet for the medium flowing between the membrane and the ring shaped edge in such a way that, when the driving medium is introduced into the smaller interior chamber, the wall of the outlet chamber for the driving medium, a. e. the expansion chamber, opposite to the membrane, is entirely open or runs into a sound funnel in such a way that the vibrations of those parts of the Specification of Letters Patent.

Patented Apr. 13, 1920.

Application filed April 15, 1919. Serial No. 290,297.

membrane that are not covered by the inlet pipe or the inlet chamber as dlrectly as possible may be sent out through the open side of the outlet chamber or through the funnel.

The invention is illustrated by the accompanying drawing in which Figure 1 shows a longitudinal section of the device. Fig. 2 is a front view of the same with the membrane removed. Figs. 3 and 4 show modifications of the invention.

In the form shown in Figs. 1 and 2 the membrane 1 is fastened to the edge of a conical casing 3. in a suitable manner, for instance by means of a threaded ring 2. The funnel or horn element 4 is connected with the opposite, narrower edge of the casing 3, which latter on its outer side is provided with a connecting branch 5 for the driving medium. A pipe 6 arranged obliquely in relation to the longitudinal axis of the casing 3 leads from the connecting branch 5 to the central part of the membrane 1 against which its edge 7 rests.

The driving medium is admitted through the connecting branch 5 and the pipe 6 and pressed between the edge 7 of the latter and the membrane 1 into the surrounding casing 3 from where it escapes through the funnel 4. It is evident that in this way no special part of the membrane 1 will be employed for admitting the driving medium as this is introduced against only a small part of the surface of the membrane, and thus it is not necessary to make this membrane larger than what is required for the same in its capacity of sound producer. The apparatus is also easy to manufacture and has a small diameter in proportion to its forceof sound.

The pipe 6 may be stayed by means of a strengthening rib 8 arranged between the same and the side of the casing 3 opposite to the connecting branch 5.

In order to keep the ring 2 from loosening during the vibrations said ring may be provided with a recess or the like in its outer edge wherein the free end of a spring 10 or the like engages in such a way that the rotation of the ring 2 is prevented. The spring 10 is fastened to the casing 3 by means of screws or the like 9.

'In Fig. 3 the inlet pipe 12 has the shape of an annular groove the ed e of which rests against the membrane in t e same way as the pipe shown in Fig. 1. in this way the central part of the membrane will freely face the funnel, and yet the pressure medium strikes the membrane in an easily flexible place and the vibrations are also sent out from the peripheral part of the membrane. The strengthening rib 13 may also be given the shape of a pipe directly. connected with the admission pipe in about the same way as is shown in Fig. 4.

In Fig. 4 two or more admission pipes l-l, 15 rest with their free edges against the membrane. These edges are annular but of course they may also have other forms, for instance segmental when four inlet pipes are used. These different pipes may either extend radially from a common inlet pipe' or also extend through the wall of the outlet chamber where they are connected for instance with an annular chamber 16.

The wall of the outlet chamber is, as shown in Fig. 1, provided with a hole 11 for drawing off water of condensation when steam is used as driving medium.

As the inlet pipe is proportionally small in diameter the driving medium Wlll be allowed freely to escape through the funnel 4 after it has passed the annular edge.without being checked b anything that might have a disturbing e "ect upon the function of the apparatus. Thus the diameter of the membrane .need not be enlarged and the relation between the effective surface of vibration and the effective surface of pressure may be chosen in such a way that the highest possible efiiciency is obtained without taking any hindering parts in the interior of the apparatus into consideration.

A cover (not shown) may be applied outside of the membrane so as to protect the same. This cover is suitably provided with recesses or perforations in order to transmit the sound waves in the highest possible deree.

What I claim as new and desire to secure by Letters Patent is:

1. In a diaphragm horn, a conical casing decreasin in diameter forwardly and provided at 1ts forward reduced end with an opening which is concentric with relation to the casing, a horn element secured at the opening, a vibratory diaphragm held to the rear large end of the casing, and an inlet pipe arran ed diagonally within the conical casing an extending rearwardly through one side thereof, said inlet pipe having an annular surface contacting with the inner face of the diaphragm, said surface being concentric with relation to the casing, and a radial rib connected with the casing and with the inlet pipe.

2. In a diaphragm horn, a casing, an amplifier secured to the front end of the casing, a diaphragm mounted in the rear end of the casing, a hollow inlet element extending through the-side of the casing to introduce fluid to the rear side of the diaphragm, and supporting means extending between the hollow element and the inner surface of the casing.

. In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HBLGE SVEN ALBERT RYDBERG.

Witnesses:

A. W. ANDERSON, FREDFLERON. 

